[manpage] don't emit OSC 8 hyperlinks for anchor references (sphinx-d…

…oc#12108)

A reference like ":ref:`Some other page <some-other-page>`" results
in a refuri "#some-other-page".  This does not seem useful to readers
of the man page. It is especially unhelpful when using a terminals
that implements a hint mode for selecting links -- the extra links
add noise, making it harder to select the interesting ones.

While at it, relax the restriction that "man_show_urls" is limited
to mailto/http/ftp URLs; I don't see why other protocols shouldn't
be allowed.

Follow up to sphinx-doc#12108

I also confirmed that even with docutils 0.21 we do not need to
override depart_reference because we already skip reference nodes.

sphinx/writers/manpage.py

@@ -309,7 +309,8 @@ def visit_image(self, node: Element) -> None:
  # overwritten -- don't visit inner marked up nodes
  def visit_reference(self, node: Element) -> None:
  uri = node.get('refuri', '')
- if uri:
+ is_local_reference = uri.startswith('#')
+ if uri and not is_local_reference:
  # OSC 8 link start (using groff's device control directive).
  self.body.append(fr"\X'tty: link {uri}'")
 
@@ -319,7 +320,7 @@ def visit_reference(self, node: Element) -> None:
  self.visit_Text(node)
  self.body.append(self.defs['reference'][1])
 
- if uri.startswith(('mailto:', 'http:', 'https:', 'ftp:')):
+ if not is_local_reference:
  # if configured, put the URL after the link
  if self.config.man_show_urls and node.astext() != uri:
  if uri.startswith('mailto:'):
@@ -328,7 +329,7 @@ def visit_reference(self, node: Element) -> None:
  ' <',
  self.defs['strong'][0], uri, self.defs['strong'][1],
  '>'])
- if uri:
+ if uri and not is_local_reference:
  # OSC 8 link end.
  self.body.append(r"\X'tty: link'")
  raise nodes.SkipNode